/**
 * 判断输入的是否是一个合法的手机号
 * @param {*} str 
 */
function isValidPhoneNumber(str){
  return /^(\+86)?1[3-9]\d{9}$/.test(str);
}
console.log(isValidPhoneNumber('18910009876'));
console.log(isValidPhoneNumber('+8618910009876'));
console.log(isValidPhoneNumber('1891000987'));
console.log(isValidPhoneNumber('189100098769'));